The answer to our water quality issues lies in the soil, Ken Calvert writes.
United States President Donald Trump is n hot water for wanting to ‘‘drain the swamp’’.
But, to strain the metaphor, our nation’s dairy farmers are also getting themselves in trouble because they, and their ancestors, have done just that.
The Southland plain is rich, green farmland because my great-grandfather, and other pioneers, worked hard to turn the flax, rushes, water, manuka and matagouri into prosperity.
But the thousands of kilometres of drains they created are now almost a liability. The only thing between our excretory livestock and our recreational waterways is a foot of topsoil.
We want our rivers to run clean but not green. We want to stay healthy, too. Nasty faecal coliforms that can make us sick should have no place in our waterways.
It is nature, the ‘‘earthworms’’ and micro-organisms below them in the food chain, we must rely on.
So, what’s the problem given the biological content of our soils?
There is a rapidly escalating body of experience, from the ‘‘biological’’ farming fraternity that fingers the overuse of highly soluble, quick-acting fertilisers.
It only takes 3% of salt in seawater to make it undrinkable, and less than that of the likes of urea and super phosphate, to sicken something along that soil food web or food chain and upset the system.
There are much less soluble and slower-acting fertilisers that will still tick all the boxes and keep our earthworm population, nature’s drainage system, busy. It’s not more antiseptics, disinfectants and fancy chemicals (they only add to the problem), it is soil biology and one foot of fertile topsoil that can come to our rescue.
●Ken Calvert is president of the Southland Worm Breeders Association.